When fitting a lot of toner cartridges (not Brother or Oki), you have to remove a ribbon that allows the toner in the cartridge to be used. When toner cartridges are built the toner hopper part, where the toner is stored, is sealed by a ribbon to allow manufacture. On fitting the toner cartridge to your printer you need to remove this ribbon. You do this by pulling on a tab on the side of the cartridge which enables you to pull out the ribbon and release the toner.
When pulling the tape out always do it with a straight pull, or it may not come all the way out.
Always do this after giving the toner cartridge a shake to distribute the toner in the cartridge.
The picture below shows the toner hopper you are releasing the toner from.
If you have any problems please call 01522 683460 and we will do our best to help.